The present disclosure describes a packaging configuration used for a small coin-sized electroacupuncture (EA) stimulator of the type described in the related applications referenced above, or equivalent small, thin, self-contained stimulators adapted for implantation under the skin. More particularly, the present disclosure relates to improvements in a radial feed-through pin that may be used as part of the packaging configuration of a small coin-sized, hermetically-sealed case that houses an implantable electroacupuncture device (IEAD), or equivalent electronic stimulation circuitry. Such feed-through pin provides a reliable and easy-to-manufacture electrical connection for use between electronic output circuitry of the IEAD housed within the coin-sized case, and an anode electrode secured to the outside of the case.
As indicated in the preceding paragraph, in an IEAD of the type disclosed in the applications referenced above, a feed-through pin is required to connect the electronics output from inside the hermetically-sealed, thin-profile, titanium or stainless steel implant case to a anode electrode on the outside of the case.
Note, as used herein, the term “feed-through” pin refers to the electrical conductive path made between electronic circuitry inside of an hermetically-sealed case, and to wires and/or electrodes on the outside of the hermetically-sealed case. The conductive path used to make such a feed-through path is typically a metal pin that passes through a bead of Ruby, ceramic (such as, e.g., Alumina) or glass or some other type of electrical-insulator material that is brazed or bonded to the metal case (to prevent the conductive pin from being electrically shorted to the metallic case). The electrically conductive pin thus feeds an insulated electrical connection through the metallic wall of the hermetically-sealed case, without being shorted to the metallic wall, while maintaining the hermeticity of the sealed case. Such a “feed-through pin” may also be referred to herein by many other, but equivalent terms. For example, the adjective phrase “feed-through” may be spelled different ways, such as “feedthrough”, “feed through”, “feed thru”, or “feedthru”, all used to modify the noun “pin”, or “wire”, or “conductor”, or “conductive path”, or “assembly”, or similar terms. Sometimes, the adjective “feed-through”, or variations thereof, is simply used as a noun. E.g., a feed-through pin or feed-through assembly may be referred to simply as a “feed through” or a “feedthru”.
A major difficulty with placing a feed-through insulator and pin so that it passes through an hermetically sealed case wall is to keep the feed-through insulator and brazed joint a safe distance from where the metal case is welded, typically using laser seam welding. Otherwise, the feed-through insulator and the brazed interface, and its resulting assembly (of a Ruby or Ceramic (e.g., Alumina) bead or other insulative bead that surrounds the pin) can easily be damaged by the high temperatures associated with the welding.
Another difficulty associated with the location of the feed-through pin is the orientation of the feed-through pin relative to the case wall. For relatively thick cases, short feed-through pins can be placed in just about any location and orientation relative to the case wall. In such instance, it is thus a relatively straight forward design to place the feed-through pins as far away from the welded seams as possible to minimize any potential thermal damage during assembly and welding of the case. However, for thin cases, e.g., coin-size cases of the type used by an IEAD of the type described above, about the only option for placing a feed-through pin is to place it radially so as to pass through the perimeter edge of the case. However, such placement typically places the pin much too close to the welded seam of the case, and therefore subjects the pin assembly to very high, potentially damaging, temperatures when the case is welded closed.
What is needed, therefore, is a packaging configuration for a coin-sized hermetically-sealed case that allows a radial feed-through insulator and pin to be used, but that also protects such pin, insulator and brazed joint from dangerously high temperatures during the manufacturing process. Such a packaging configuration is described and claimed herein.
As background regarding the need for, design and use of an implantable electroacupuncture device (IEAD) of the type described in the references cited above, a brief history of acupuncture and electroacupuncture (EA) will next be presented.
Traditional acupuncture and acupressure has been practiced in Eastern civilizations (principally in China, but also in other Asian countries) for at least 2500 years. It is still practiced today throughout many parts of the world, including the United States and Europe. Acupuncture is an alternative medicine that treats patients by insertion and manipulation of needles in the body at selected points.
The locations where the acupuncture needles are inserted are referred to as “acupuncture points” or simply just “acupoints”. The location of acupoints in the human body has been developed over thousands of years of acupuncture practice, and maps showing the location of acupoints in the human body are readily available in acupuncture books or online. An excellent reference book that identifies all of the traditional acupoints within the human body is WHO STANDARD ACUPUNCTURE POINT LOCATIONS IN THE WESTERN PACIFIC REGION, published by the World Health Organization (WHO), Western Pacific Region, 2008 (updated and reprinted 2009), ISBN 978 92 9061 248 7 (hereafter “WHO Standard Acupuncture Point Locations 2008”). The Table of Contents, Forward (page v-vi) and General Guidelines for Acupuncture Point Locations (pages 1-21) of the WHO Standard Acupuncture Point Locations 2008 are incorporated herein by reference.
Acupoints are typically identified by various letter/number combinations, e.g., L6, S37. The maps that show the location of the acupoints may also identify what condition, illness or deficiency the particular acupoint affects when manipulation of needles inserted at the acupoint is undertaken.
It is noted that references to the acupoints in the literature are not always consistent with respect to the format of the letter/number combination. Some acupoints are identified by a name only, e.g., Tongli. The same acupoint may be identified by others by the name followed with a letter/number combination placed in parenthesis, e.g., Tongli (HT5). Alternatively, the acupoint may be identified by its letter/number combination followed by its name, e.g., HT5 (Tongli). The first letter typically refers to a body organ, or other tissue location associated with, or affected by, that acupoint. However, usually only the letter is used in referring to the acupoint, but not always. Thus, for example, the acupoint ST40 is the same as acupoint Stomach 40 which is the same as ST-40 which is the same as ST 40 which is the same as Fenglong. For purposes of this patent application, unless specifically stated otherwise, all references to acupoints that use the same name, or the same first letter and the same number, and regardless of slight differences in second letters and formatting, are intended to refer to the same acupoint.
As an alternative to traditional acupuncture, some have proposed applying moderate electrical stimulation at selected acupuncture points through needles that have been inserted at those points. See, e.g., http://en.wikipedia.org/wiki/Electroacupuncture. Such electrical stimulation is known as electroacupuncture (EA). According to Acupuncture Today, a trade journal for acupuncturists: “Electroacupuncture is quite similar to traditional acupuncture in that the same points are stimulated during treatment. As with traditional acupuncture, needles are inserted on specific points along the body. The needles are then attached to a device that generates continuous electric pulses using small clips. These devices are used to adjust the frequency and intensity of the impulse being delivered, depending on the condition being treated. Electroacupuncture uses two needles at a time so that the impulses can pass from one needle to the other. Several pairs of needles can be stimulated simultaneously, usually for no more than 30 minutes at a time.” “Acupuncture Today: Electroacupuncture”. Feb. 1, 2004 (retrieved on-line Aug. 8, 2006 at http://www.acupuncturetoday.com/abc/electroacupuncture.php).
U.S. Pat. No. 6,735,475, issued to Whitehurst et al., discloses use of an implantable miniature neurostimulator, referred to as a “microstimulator,” that can be implanted into a desired tissue location and used as a therapy for headache and/or facial pain. The microstimulator has a tubular shape, with electrodes at each end.
Other patents of Whitehurst et al. teach the use of this small, microstimulator, placed in other body tissue locations, including within an opening extending through the skull into the brain, for the treatment of a wide variety of conditions, disorders and diseases. See, e.g., U.S. Pat. No. 6,950,707 (obesity and eating disorders); U.S. Pat. No. 7,003,352 (epilepsy by brain stimulation); U.S. Pat. No. 7,013,177 (pain by brain stimulation); U.S. Pat. No. 7,155,279 (movement disorders through stimulation of Vagus nerve with both electrical stimulation and drugs); U.S. Pat. No. 7,292,890 (Vagus nerve stimulation); U.S. Pat. No. 7,203,548 (cavernous nerve stimulation); U.S. Pat. No. 7,440,806 (diabetes by brain stimulation); U.S. Pat. No. 7,610,100 (osteoarthritis); and U.S. Pat. No. 7,657,316 (headache by stimulating motor cortex of brain).
Techniques for using electrical devices, including external EA devices, for stimulating peripheral nerves and other body locations for treatment of various maladies are known in the art. See, e.g., U.S. Pat. Nos. 4,535,784; 4,566,064; 5,195,517; 5,250,068; 5,251,637; 5,891,181; 6,393,324; 6,006,134; 7,171,266; and 7,171,266. The methods and devices disclosed in these patents, however, typically utilize (i) large implantable stimulators having long leads that must be tunneled through tissue or blood vessels over an extended distance to reach the desired stimulation site, (ii) external devices that must interface with implanted electrodes via percutaneous leads or wires passing through the skin, or (iii) inefficient and power-consuming wireless transmission schemes. Unfortunately, in Applicant's view, such devices and methods are still far too invasive, or are ineffective, and/or are much too expensive, and thus do not provide a viable means for providing needed medical therapy for a patient.
From the above, it is seen that there is a need in the art for a more affordable, less invasive device and technique for electroacupuncture stimulation of acupoints that does not require the continual use of needles inserted through the skin, or long insulated wires implanted or inserted into blood vessels, for the purpose of treating an illness or deficiency of a patient.